This invention pertains generally to a process for preparing liquid concentrates, and more particularly to a process for preparing liquid additive and color concentrates used in the manufacture of plastic parts. The invention also relates to a dispensing system for preparing liquid concentrates for plastics.
Liquid concentrates have been used for coloring and modifying plastic resins to produce colored or modified plastic parts. Such liquid concentrates may be added directly to a molding machine or extruder (or through a mixing process which pre-mixes the liquid concentrate with one or more resins and other materials in either a melted or solid state) to incorporate color and/or other modifiers into the plastic part. Traditionally, a plastic part manufacturer places an order with a concentrate manufacturer for a specific color or other additive concentrate. The concentrate is then prepared according to the customer""s specification and shipped. In the alternative, the concentrate manufacturer may be requested to develop an appropriate formulation of the liquid concentrate to achieve the color and/or other attributes desired by the plastic part manufacturer or a customer or supplier of the plastic part manufacturer. The manufacturer will then provide samples or molded color chips or parts for evaluation and approval by the customer. This process of developing, sampling, evaluating and approving formulations followed by ordering, producing and shipping liquid concentrates can take several days and often takes several weeks.
This traditional manner for developing, sampling, evaluating and approving formulations for liquid concentrates followed by the order, production and shipping of liquid concentrates has several significant drawbacks. There is significant lead time between the time the specification for the liquid concentrate is provided to the concentrate manufacturer (whether for the concentrate itself or for the final plastic part which requires the development and approval of a formulation) and the time the order is placed for a particular liquid concentrate and when that concentrate is actually received. Plastic part manufacturers often must wait for samples (in many cases numerous successive samples) to be produced for evaluation before approval of a particular custom liquid concentrate to achieve specific color and/or additive requirements. At present, therefore, the user of the liquid concentrate must be able to accurately forecast his needs several weeks in advance and place an appropriate order for a liquid concentrate, taking into account the additional time which may be required to develop, sample, evaluate and approve the liquid concentrate which will be ordered, produced and shipped to manufacture the particular plastic parts. This requires the user to have an accurate forecast of its own customer demands for manufactured plastic parts. After concentrates are approved, because of the lead time required to receive an order, the user must carry an inventory of concentrates, each of which will have been custom formulated and not capable of being used in a wide spectrum of plastic parts of varying color or additive requirements. Such an inventory of liquid concentrates is both expensive to purchase as well as costly to warehouse. Moreover, such an inventory may become obsolete over a period of time as orders for plastic parts change.
From the foregoing, it is appreciated that there exists a need for an improved process by which a manufacturer of plastic parts can obtain liquid concentrates more quickly to satisfy changing customer order flow. This process should shorten the time required to sample, evaluate and approve a liquid concentrate and, after such approval, shorten the time required to receive that approved concentrate to produce plastic parts while, at the same time, reducing or eliminating the need to carry an extensive inventory of liquid concentrates, with attendant costs and possibility for loss. In particular, there is a need for the decentralized production of liquid concentrates so that liquid concentrate formulas can be sampled and produced promptly in response to customer demand. The present invention provides such a process.
The invention provides a process for preparing a liquid concentrate for use in coloring or modifying manufactured plastic parts. In particular, the present inventive process for preparing a liquid concentrate comprises:
(a) preparing one or more liquid intermediates, wherein the liquid intermediates comprise a liquid vehicle and at least one pigment, dye or other additive;
(b) standardizing the liquid intermediates;
(c) transferring the standardized liquid intermediates to a remote location; and
(d) dispensing the liquid intermediates to produce a liquid concentrate (which may be a liquid color concentrate, a liquid additive concentrate or a combination liquid color and additive concentrate), wherein the quantity of each liquid intermediate dispensed is controlled according to a predetermined formula for the liquid concentrate.
The present invention also provides a process for preparing a liquid concentrate for use in the manufacture of plastic parts comprising:
(a) providing one or more liquid intermediates, wherein the liquid intermediates comprise a liquid vehicle and at least one pigment, dye or other additive, wherein the liquid intermediates are standardized, and wherein the liquid intermediates have been prepared remotely; and
(b) dispensing the liquid intermediates to produce a liquid concentrate, wherein the quantity of each liquid intermediate dispensed is controlled according to a predetermined formula for the liquid concentrate.
Another process for preparing a liquid concentrate according to the present invention comprises:
(a) providing a plurality of liquid intermediates, wherein the liquid intermediates comprise a liquid vehicle and at least one colorant (sometimes referred to herein as a liquid color intermediate), wherein the tint strength, color hue and viscosity of each liquid intermediate is standardized, and wherein the liquid intermediates are prepared remotely; and
(b) dispensing the liquid intermediates to produce a liquid concentrate, wherein the quantity of each liquid intermediate dispensed is controlled according to a predetermined gravimetric formula for the liquid concentrate, wherein the quantity of each liquid intermediate is controlled by a computer that contains the predetermined gravimetric formula, and wherein the dispensing of the liquid intermediates is controlled by the computer.
The present invention further includes a dispensing system for preparing a liquid concentrate comprising:
(a) a plurality of containers each containing a standardized liquid intermediate prepared at a location remote from the dispensing system; and
(b) a dispensing machine for dispensing one or more of the liquid intermediates to produce a liquid concentrate, wherein the quantity of each liquid intermediate dispensed is controlled according to a predetermined gravimetric formula for the liquid concentrate, wherein the quantity of each liquid intermediate is controlled by a computer that contains the predetermined gravimetric formula, and wherein the dispensing of the liquid intermediates is controlled by the computer.
The process and dispensing system of the present invention advantageously permit the production of liquid intermediates and liquid concentrates having very tight tolerances with respect to the physical characteristics of the liquid intermediates and liquid concentrates such as, for example, tint strength, color hue and viscosity. These and other advantages of the present invention, as well as additional inventive features, will be apparent from the description of the invention provided herein.